Conventional techniques for achieving sustained or delayed release of medicaments for oral ingestion involve the pre-treatment of the drug with a material to make it less soluble in the fluids of the stomach and the intestinal tract. Water-insoluble film forming polymers are widely used for this purpose as are waxes and fats that require digestion by the bile fluids to release entrapped medication.
Materials are also commonly employed which erode gradually or develop porosity to release entrapped medicaments. These can involve similar polymers or waxes that form the structures or gels through which the aqueous digestive fluids can travel to extract the medication and make it available for absorption.
In general, these techniques for achieving delayed drug availability require rather complex methodologies for coating the particles of drug or for preparing the dosage form of the drug. This complexity introduces a dimension of variability which makes it necessary to carefully monitor the rate of drug release of each batch of product in-vitro by measuring drug dissolution against some standard in order to assure the reproducibility of drug delivery form each batch of finished product.
During experimentation on the orally ingestible compositions disclosed in the parent application hereof, it was noted that when the compositions which contained soluble alginates and antacids in the form of polyvalent cation salts were exposed to hydrochloric acid of stomach acid strength, the compositions formed a gummy glutinous adhesive mass out of which the major antacid portion leached slowly, rather than rapidly as initially expected. Further investigations led to the formulation of the compositions disclosed and claimed herein.